The main issue I've read that doesn't relate to schisms is that people bring in priests as spies and saboteurs.
A solution that doesn't seem hard to code, and more of a tweak:
Make it so that Aspirant ranked priests can only Preach and Pray for Signs. Some features are already only available to Elders after promotion. By demotion it would act similar to how Exiles work in a realm heirarchy.
Have a priests that's a pain in the ass? Demote him to aspirant so he can't do any negative actions. Worried about spies? Send messages to full members only. It's not like if you're truely worried about spies that you aren't already doing this anyways, since ANYONE can join ANY guild so long as they're not trying to join a second religion simultaneously.
